Added a bunch of table tests to select

And some hints regarding additional tests and how to turn them of for
subselects

include/sqlpp11/alias.h

@@ -44,6 +44,7 @@ namespace sqlpp
 			};
 
 			using _name_t = typename AliasProvider::_name_t;
+			using _table_set = typename Expression::_table_set;
 
 			Expression _expression;
 		};

include/sqlpp11/select.h

@@ -391,9 +391,6 @@ namespace sqlpp
 				return _column_list_t::static_size() + get_dynamic_names().size();
 			}
 
-			template<typename Db>
-				struct can_run_t
-				{
 					/*
 					static_assert(column_list::_table_set::template is_subset_t<_from_t::_table_set>::value
 					static_assert(detail::is_subset_of<column_list::_table_set, _from_t::_table_set>::value
@@ -406,8 +403,10 @@ namespace sqlpp
 					//static_assert(is_where_t<Where>::value, "cannot run select without having a where condition, use .where(true) to select all rows");
 					// FIXME: Check for missing aliases (if references are used)
 					// FIXME: Check for missing tables, well, actually, check for missing tables at the where(), order_by(), etc.
-
-					static constexpr bool value = true;
+			template<typename A>
+				struct is_table_subset_of_from
+				{
+					static constexpr bool value = ::sqlpp::detail::is_subset_of<typename A::_table_set, typename From::_table_set>::value;
 				};
 
 			// Execute
@@ -415,7 +414,16 @@ namespace sqlpp
 				auto _run(Db& db) const
 				-> result_t<decltype(db.select(*this)), _result_row_t<Db>>
 				{
-					static_assert(can_run_t<Db>::value, "Cannot execute select statement");
+#warning: need to check in add_xy method as well
+#warning: need add_wxy_without_table_check
+#warning: might want to add an .extra_tables() method to say which tables might also be used here, say via dynamic_from or because this is a subselect
+					static_assert(is_table_subset_of_from<ColumnList>::value, "selected columns require additional tables in from()");
+					static_assert(is_table_subset_of_from<Where>::value, "where() expression requires additional tables in from()");
+					static_assert(is_table_subset_of_from<GroupBy>::value, "group_by() expression requires additional tables in from()");
+					static_assert(is_table_subset_of_from<Having>::value, "having() expression requires additional tables in from()");
+					static_assert(is_table_subset_of_from<OrderBy>::value, "order_by() expression requires additional tables in from()");
+					static_assert(is_table_subset_of_from<Limit>::value, "limit() expression requires additional tables in from()");
+					static_assert(is_table_subset_of_from<Offset>::value, "offset() expression requires additional tables in from()");
 					static_assert(_get_static_no_of_parameters() == 0, "cannot run select directly with parameters, use prepare instead");
 					return {db.select(*this), get_dynamic_names()};
 				}
@@ -425,7 +433,6 @@ namespace sqlpp
 				auto _prepare(Db& db) const
 				-> prepared_select_t<Db, select_t>
 				{
-					static_assert(can_run_t<Db>::value, "Cannot prepare select statement");
 
 					return {{}, get_dynamic_names(), db.prepare_select(*this)};
 				}

include/sqlpp11/vendor/from.h

@@ -51,7 +51,7 @@ namespace sqlpp
 
 				static_assert(::sqlpp::detail::all_t<is_table_t, Tables...>::value, "at least one argument is not a table or join in from()");
 
-				using _table_set = typename ::sqlpp::detail::make_joined_set<typename Tables::_table_set...>;
+				using _table_set = ::sqlpp::detail::make_joined_set_t<typename Tables::_table_set...>;
 
 
 				from_t(Tables... tables):

include/sqlpp11/vendor/group_by.h

@@ -78,6 +78,7 @@ namespace sqlpp
 		struct no_group_by_t
 		{
 			using _is_noop = std::true_type;
+			using _table_set = ::sqlpp::detail::type_set<>;
 		};
 
 		// Interpreters

include/sqlpp11/vendor/having.h

@@ -75,6 +75,7 @@ namespace sqlpp
 		struct no_having_t
 		{
 			using _is_noop = std::true_type;
+			using _table_set = ::sqlpp::detail::type_set<>;
 		};
 
 		// Interpreters

include/sqlpp11/vendor/limit.h

@@ -29,6 +29,7 @@
 
 #include <sqlpp11/type_traits.h>
 #include <sqlpp11/vendor/policy_update.h>
+#include <sqlpp11/detail/type_set.h>
 
 namespace sqlpp
 {
@@ -40,6 +41,7 @@ namespace sqlpp
 			{
 				using _is_limit = std::true_type;
 				static_assert(is_integral_t<Limit>::value, "limit requires an integral value or integral parameter");
+				using _table_set = ::sqlpp::detail::type_set<>;
 
 				limit_t(Limit value):
 					_value(value)
@@ -93,6 +95,7 @@ namespace sqlpp
 		struct no_limit_t
 		{
 			using _is_noop = std::true_type;
+			using _table_set = ::sqlpp::detail::type_set<>;
 		};
 
 		// Interpreters

include/sqlpp11/vendor/offset.h

@@ -29,6 +29,7 @@
 
 #include <sqlpp11/type_traits.h>
 #include <sqlpp11/vendor/policy_update.h>
+#include <sqlpp11/detail/type_set.h>
 
 namespace sqlpp
 {
@@ -93,6 +94,7 @@ namespace sqlpp
 		struct no_offset_t
 		{
 			using _is_noop = std::true_type;
+			using _table_set = ::sqlpp::detail::type_set<>;
 		};
 
 		// Interpreters

include/sqlpp11/vendor/order_by.h

@@ -33,6 +33,7 @@
 #include <sqlpp11/vendor/interpretable.h>
 #include <sqlpp11/vendor/policy_update.h>
 #include <sqlpp11/detail/logic.h>
+#include <sqlpp11/detail/type_set.h>
 
 namespace sqlpp
 {
@@ -75,6 +76,7 @@ namespace sqlpp
 		struct no_order_by_t
 		{
 			using _is_noop = std::true_type;
+			using _table_set = ::sqlpp::detail::type_set<>;
 		};
 
 		// Interpreters

tests/SelectTest.cpp

@@ -61,13 +61,11 @@ int main()
 		const std::string b = row.tabBar.beta;
 	}
 
-#warning this should fail because f is not in from()
-	for (const auto& row : db(select(f.omega, all_of(t).as(t), t.gamma).from(t).where(true)))
+	for (const auto& row : db(select(all_of(t).as(t), t.gamma).from(t).where(t.alpha > 7)))
 	{
 		int64_t a = row.tabBar.alpha;
 		const std::string b = row.tabBar.beta;
 		const bool g = row.gamma;
-		const float o = row.omega;
 	}
 
 	return 0;